The present invention is directed to a double-sided pressure-sensitive adhesive tape and, more particularly, to a double-sided single-liner pressure-sensitive adhesive tape which employs silicone adhesive, even highly-aggressive silicone adhesive, on one side of a carrier web, and achieves good balance of tack, adhesion and shear utilizing only a single release liner.
Double-sided pressure-sensitive adhesive tapes are known, including tapes which are wound with two release liners to achieve required ease of unwind and to avoid blocking of the tape roll. Examples include acrylic/silicone double-sided tapes, such as commercial tape product No. 9731 available from 3M Company (Minneapolis, Minn., USA) and commercial tape product No. 2178 available from John Deal Coatings, Inc. (Mount Julient, Tenn., USA) It is disadvantageous, however, to deal with two release liners when applying a double-sided tape, the second release liner adds waste and application complexity.
Also known are double-sided pressure-sensitive adhesive tapes which use one or even no release liners. As described in the background discussion in U.S. Pat. No. 5,372,865, a double-sided pressure-sensitive tape which does not use a release liner is known, in which an acrylic pressure-sensitive adhesive is used on one side and a rubber-based pressure-sensitive adhesive is used on the opposite side of the carrier web. Several draw backs for such known double-sided tapes are mentioned in that patent. Notably, the limitation of the pressure-sensitive adhesives used in such known double-sided tapes to acrylic pressure-sensitive adhesives and rubber-based pressure-sensitive adhesives is a significant disadvantage, in view of their low adhesive force and other poor performance characteristics.
It is an object of the present invention to overcome some or all of the foregoing disadvantages of known double-sided pressure-sensitive adhesive tapes. It is a particular object of at least certain preferred embodiments of the invention to provide double-sided adhesive tapes having predictable and controllable unwind force and excellent resistance to blocking. It is a further object of certain preferred embodiments to provide double-sided adhesive tapes employing only a single release liner. It is a further object of certain preferred embodiments of the invention to provide a double-sided single-liner pressure-sensitive adhesive tape, that is, a double-sided pressure-sensitive adhesive tape wound with only a single, double-sided release liner, which tape exhibits excellent adherence to silicone foam or silicone rubber or the like, silicone treated surfaces, low energy surfaces, and/or irregular surfaces, for fire and heat resistant seals.
These and additional objects and features of the invention will be understood by those skilled in the art from the following disclosure and from the discussion thereafter of certain preferred embodiments.
In accordance with a first aspect, a double-sided single-liner pressure-sensitive adhesive tape is provided, having a layer of first pressure-sensitive adhesive on a first surface of a flexible carrier web and a layer of silicone pressure-sensitive adhesive on a second surface of a carrier web. The double-sided tape is wound with a differential double-sided release liner. A layer of first release material is provided on a first surface on a flexible release liner web facing the first pressure-sensitive adhesive. A layer of fluorosilicone release material is provided on a second surface of the release liner web facing the silicone pressure-sensitive adhesive.
In accordance with another aspect, certain preferred embodiments of the invention employ highly aggressive silicone pressure-sensitive adhesive, that is, silicone PSA having high adhesive value. Especially preferred is silicone PSA having substantial phenyl content, such as polydimethyl(diphenyl)silicone PSA having about 4% to 20% phenyl content, more preferably 10% to 20% phenyl content, that is, 4% to 20% and 10% to 20% respectively, phenyl group replacement of methyl groups in the silicone polymer. Exemplary such phenyl content silicone adhesive can be prepared as the reaction product of polydimethyl(diphenyl)siloxane gums and polydisiloxane resin in accordance with known adhesives technology. It will be recognized to be a significant advantage, that a single-liner tape is thereby provided, that is, a double-sided pressure-sensitive adhesive tape employing only a single release liner, with highly adhesive silicone pressure-sensitive adhesive suitable, for example, in certain highly preferred embodiments, to form a fire and heat resistant seal to a silicone foam or silicone rubber substrate. In particular, for example, certain such preferred embodiments are found to provide adhesion to the surface of silicone foam and rubber, and to have a flame resistance rating of HF-1/HBF as measured by UL-94 test method, and temperature resistance sufficient for passing hot flex at 230xc2x0 C. as measured by ASTM-0573.
In accordance with a second aspect, a double-sided single-liner pressure-sensitive adhesive tape comprises a double-sided carrier web as described above with a differential release liner, at least one side of which is coated with fluorosilicone and the opposite side of which is coated with silicone or fluorosilicone.
In accordance with another aspect, certain preferred embodiments of the invention have a layer of acrylic pressure-sensitive adhesive disposed on a first surface of a flexible carrier web, and a layer of silicone pressure-sensitive adhesive on the opposite surface of the carrier web, preferably a high adhesive value silicone PSA having phenyl group content of about 4% to 20%, more preferably having a high phenyl group content of 10% to 20%. A double-sided differential release liner has a silicone release material on a first surface of a release liner web facing the acrylic pressure-sensitive adhesive. A layer of fluorosilicone release material is coated on the second surface of the release liner web facing the silicone pressure-sensitive adhesive.
Those skilled in the art will recognize that the double-sided single-liner pressure-sensitive adhesive tapes disclosed here represent a significant technological advance. Preferred embodiments disclosed above and further discussed below are found to have excellent resistance to blocking, and to demonstrate desirable unwind forces. Certain preferred embodiments employing aggressive silicone PSA on the second surface, especially high phenyl content silicone PSA, exhibit excellent adherence to silicone foam or silicone rubber for fire and heat resistant seals. Also, certain preferred embodiments have excellent adherence to silicone treated surfaces, low energy surfaces and/or irregular surfaces, etc. More generally, preferred embodiments of the double-sided single-liner pressure-sensitive adhesive tapes disclosed here are found to provide good balance of tack, adhesion and shear. These and additional features and advantages of the present invention will be further understood from the following detailed discussed of certain preferred embodiments.